In order to design efficient CVs, we follow the approach of Ref. bonati2020data that relies on the linear discriminant analysis (LDA) introduced a long time ago by Fisher[1]}. We specialize our discussion to the case in which only two metastable states are present since here we are only interested in studying transitions between solid (S) and liquid (L) phases. For a treatment of the more general case in which several metastable states are present the interested reader is referred to the literature.[2]}
